Color cathode ray tube having shadow mask frame formed to accommodate a support system



Aug. 11, 1970 KURYLA -ET Al. 3,524,096

COLOR CATHODE RAY TUBE HAVING SHADOW MASK FRAME FORMED TO ACCOMMODATE A SUPPORT SYSTEM Filed April 24, 1968 2 Sheets-Sheet 1 D E 38 r f Z8 32 34 E I Z i l6 --Pl 4 f 4]..-x l,. t

INVENTORS ALAN 1: KURYLA 8. PAUL HAAS, DECEASED BY uucuamas. EXECUTRIX BY g g/63% ATTORNEY Aug. 11, 1970 A. T. KURYLA ET A1. 3,524,096

COLOR CATHODE RAY TUBE HAVING SHADOW MASK FRAME FORMED To ACCOMMODATE A SUPPORT SYSTEM Filed April 24. 1968 I 2 Sheets-Sheet 2 INVENTORS ALAN T.- KURYLA 8: PAUL HAAS, DECEASED av nae cuMs axacuTm United States Patent COLOR CATHODE RAY TUBE HAVING SHADOW MASK FRAME FORMED TO ACCOMMODATE A SUPPORT SYSTEM Alan T. Kuryla, Geneva, N.Y., and Paul Haas, deceased, late of Seneca Falls, N.Y.,by Helen C. Haas, executrix, Seneca Falls, N.Y., assignors to Sylvania Electric Products, Inc., a corporation of Delaware Filed-Apr. 24, 1968, Ser. No. 723,830 Int. Cl. H01j 19/46, 29/46 US. Cl. 313-85 Claims ABSTRACT OF THE DISCLOSURE A mask support frame formed with rectangular slots in a plurality of the upstanding walls thereof to accommodate movement amplifying hinges of the frame support system and allow utilization of a planar instanding flange around the rim of the frame.

BACKGROUND OF THE INVENTION To prevent overscanning of the screen by the electron beams with subsequent color impurities caused by stray electrons, a beam shield has generally been formed about the upper rim of the frame. This beam shield or flange projects inwardly toward the center of the tube a prescribed distance and prevents the electron beams from impinging upon the wall of the frame, and thus substantially reduces the aforementioned color impurities. Flanges of the type described above are exemplified in US. Pat. No. 3,345,530.

Recent innovations in the frame support system to cormet for impure color problems caused by the expansion of the mask-frame assembly from the heating effect of the scanning electron beam has led to modifications in the instanding flange of the frame. An exemplary support system of this type may be found described in US. Pat. No. 3,330,980. The modification which was first adopted com prised reshaping the mask supporting frame so that in place of the planar flange the flange and wall were curved to conform to the spherical configuration of the screen. Thus, the center areas on all four sides of the frame were lower than the corners. This permitted utilization of the heat compensating frame support system which utilized an instanding movement amplifying hinge. The lower center areas permitted free movement of the hinge. While this system provided an adequate mounting means for the frame support system, the elimination of the planar flange introduced new overscanning problems with the consequent color impurities.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of this invention to reduce or eliminate the above cited disadvantages.

It is another object of the invention to enhance color cathode ray tube manufacture.

It is yet another object of the invention to provide a shadow mask frame which is formed to accommodate a movement amplifying hinge of a frame supporting system while still maintaining the planar flange.

3,524,096 Patented Aug. 11, 1970 These objects are accomplished in one aspect of the invention by the provision, in a color cathode ray tube of the shadow mask variety, of means for supporting a mask in spaced relationship with the screen which comprises, in combination, a frame for supporting the mask and a support system for the frame. The frame comprises a substantially rectangular structure having an upstanding rim or wall which has an instanding substantially planar flange around the upper surface thereof. The support system comprises a plurality of springs attached to the frame through the intermediary of a spring mounting member, at least two of which have formed thereon an instanding movement amplification hinge. The frame is formed to provide a like number of receptive areas for the hinges.

The frame structure and frame support system described above greatly enhances color cathode ray tubes since they utilize not only the heat compensating support system but the planar flange as well.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic sectional representation of a color cathode ray tube;

FIG. 2 is an enlarged cross-sectional view taken along the line 2--2 of FIG. 1;

FIG. 3 is a plan view taken along the line 3-3 of FIG. 1; and

FIG. 4 is an elevational view of the frame taken along the line 4--4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above-described drawings.

Referring now to the drawings with greater particularity, in FIG. 1 there is diagrammatically shown a cathode ray tube 10 having a screen 12 comprised of a multiplicity of phosphor triads formed on the inside surface of the screen faceplate 14 in a manner well known in the art. Positioned adjacent the screen 12 and spaced therefrom is a substantially rectangular foraminous shadow mask 16 which is attached at its peripheral edge to a mask supporting frame 18 having formed around its upper rim an instanding flange 19. A source of electrons 20 is positioned in the neck 22 of tube 10, and may comprise a plurality of individual electron guns as is also well known in the art.

The support system 24 is shown in greater detail in FIG. 2 and comprises a spring 26 which is attached at one end to frame 18 through the intermediary of a spring mounting member 28. Spring mounting member 28 comprises an upper portion 30 to which is attached spring 26, a lower portion 32 which is attached to an upstanding wall 34 of frame 18, and an instanding substantially U-shaped movement amplification hinge 36 which joins the upper and lower portions. The frame 18 is formed to provide receptive areas 38 to accept the instanding hinge 36 without interfering with the operation thereof and in this instance is shown as being a slot 40 formed in wall 34. Also, in this instance, slot 40 is shown as having a substantially rectangular configuration (see FIG. 4); however, the shape of the slot will be dictated by the configuration of the hinge to be positioned therewithin. The utilization of this form of support allows the employment of the instanding planar flange 19 which is joined to the upper rim of frame wall 34. It is noted above that the use of the planar flange provides many advantages among which are: greater strength for the frame; better protection for the screen against over-scan- 3 ning of the electron beam; and greater protection from the earths magnetic field.

The entire mask-frame assembly is supported within the tube by means of cooperation between an aperture provided in the free .end of spring 26 and inwardly projecting studs 42 positioned interiorly of the cathode ray tube face panel. Generally, three of these mounting areas are utilized although it is contemplated that four or more may also be used. One such system is shown in FIG. 3 wherein there is illustrated a plan view of a face panel having a major axis xx and a minor axis y--y. In the embodiment shown, one stud 42 is positioned on the y axis and two studs are positioned in opposition to one and another on the x axis. The receptive areas 40 are formed so that at least two opposed ones are displaced in the same direction relative to one of the axes, in this instance the x axis. This arrangement is known as a bucking system and tends to equalize the forces generated in the support system by heat-caused expansion of the elements during tube operation. Other mounting arrangements are known and may be utilized without departing from the invention.

There has thus been provided an enhanced cathode ray tube having an improved mask mounting system which incorporates a planar beam shield for the prevention of color impurities caused by over-scan of the electron beam.

While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein Without departing from the scope of the invention as defined by the appended claims.

What 'is claimed:

1. In a color cathode ray tube of the shadow mask variety, a shadow mask, means for supporting said mask in spaced relationship with the screen comprising in combination: a frame supporting said mask and a support system for said frame; said frame comprising a sub stantially rectangular structure having an upstanding rim having an instanding, substantially planar flange around the upper surface thereof; said support system comprising a plurality of springs attached to said frame through the intermediary of a spring mounting member and at least two of said mounting members having formed thereon an instanding movement amplification hinge; and said upstanding rim being formed to provide a plurality of receptive areas for said hinges.

2. The tube of claim 1 wherein said plurality of receptive areas are hinge receiving slots formed in said rim of said frame.

3. The tube of claim 2 wherein said slots have a substantially rectangular configuration.

4. A substantially rectangular frame for supporting a foraminous electrode which comprises: an upstanding rim defining four walls and having an inwardly projecting substantially planar flange about the upper edge thereof; and a plurality of slots formed in said upstanding rim, at least one in each of three consecutive rwalls thereof.

5. The frame of claim 4 wherein said frame has a major and a minor axis and at least two opposed ones of said slots are displaced in the same direction relative to one of said axes.

References Cited UNITED STATES PATENTS 3,330,980 7/1967 Shrader 313- 3,343,024 9/1967 Torrenoe 313--92 3,449,612 6/ 1969 Zachrich 313-85 JAMES W. LAWRENCE, Primary Examiner V. LAFRANCHI, Assistant Examiner US. Cl. X.R. 313-284, 292 

